Transfer apparatus

ABSTRACT

A transfer apparatus is disclosed for transferring a light weight web from a dewatering section to a Yankee dryer. The transfer apparatus includes a looped transfer blanket which is disposed between the dewatering section and the Yankee dryer for supporting and transporting the web from the dewatering section towards the Yankee dryer. The dewatering section includes a press which defines a press nip for the passage therethrough of the web. The press nip assists in dewatering the web and guides the web. A press felt extends through the press nip and the transfer blanket also extends through the press nip. A roll is disposed downstream relative to the press nip for transferring the web from the transfer blanket and for guiding the web towards the Yankee dryer.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a transfer apparatus.

More specifically, the present invention relates to a transfer apparatusfor transferring a light weight web from a dewatering section to aYankee dryer.

2. Background Information

On lightweight grades such as tissue and Machine Glazed (MG) grades, itis important to have a closed draw between the forming section and theYankee dryer for good machine efficiency.

On typical prior art machines, the sheet is transferred from the formingsection to the Yankee dryer on a pick up felt. The sheet is transferredto the Yankee dryer with a pressure roll. In order to improve thedryness of the sheet prior to the Yankee dryer, there are often one ormore presses. These presses are double felted and typically have asuction roll inside the pick up roll loop to insure that the paperfollows the pick up felt after the press nip. The use of a suction rollis necessary to transfer the sheet to the pick up felt after the nip.However, suction rolls limit the load that can be applied in the nip toremove water due to their inherent strength limitations. In addition, adouble felted press on these lightweight grades, (less then 78 poundsper 3000 sq. ft.) results in significant rewet of the web by water fromthe bottom felt into the sheet thereby minimizing the water removalefficiency of the press.

The purpose of the present invention is to replace the bottom felt witha transfer belt or blanket that will carry the sheet without rewettingthe sheet in the sheet transfer process. The transfer belt or blanket isimpervious to water and has a smooth surface so the sheet will adhere tothe transfer belt or blanket after the press nip without the use of asuction roll.

According to the present invention there are two presses ahead of thepressure roll. The bottom felt on the second press has been replacedwith a transfer belt or blanket. Following the second press, the sheetwill follow the transfer belt or blanket since it has a smoother surfacecompared to the top felt. This allows the suction roll to be eliminatedin the press and replaced with either a plain roll or a shoe press thatallows much higher loads to be applied to the sheet in the press whichresults in much greater water removal. The sheet is carried to atransfer roll which uses vacuum to transfer the sheet to the pressureroll felt and onto the Yankee dryer surface. Since the transfer belt orblanket carries no water, there is no water transferred into the sheetwhile the sheet of paper is in contact with the transfer belt as well aswhen the sheet is transferred from the transfer belt to the pressureroll felt with a suction transfer roll.

In a similar but alternative arrangement, the transfer roll iseliminated and a suction roll is used in the pressure roll position totransfer the sheet from the transfer belt as well as apply the sheet tothe Yankee dryer.

Therefore, a primary feature of the present invention is the provisionof a transfer apparatus that overcomes the problems associated with theprior art arrangements.

Another feature of the present invention is the provision of a transferapparatus that inhibits rewetting of the web.

Other features and advantages of the present invention will be readilyapparent to those skilled in the art by a consideration of the detaileddescription of a preferred embodiment of the present invention containedherein.

SUMMARY OF THE INVENTION

The present invention relates to a transfer apparatus for transferring alight weight web from a dewatering section to a Yankee dryer.

The transfer apparatus according to the present invention includes alooped transfer blanket which is disposed between the dewatering sectionand the Yankee dryer for supporting and transporting the web from thedewatering section towards the Yankee dryer. The dewatering sectionincludes a press which defines a press nip for the passage therethroughof the web. The press nip assists in dewatering the web and guides theweb. A press felt extends through the press nip and the transfer blanketalso extends through the press nip. A roll is disposed downstreamrelative to the press nip for transferring the web from the transferblanket and for guiding the web towards the Yankee dryer.

In one embodiment of the present invention, the press includes a pressroll for guiding the web. A backing roll cooperates with the press rollsuch that the press roll and the backing roll define therebetween thepress nip for the passage therethrough of the web. The press feltextends through the press nip such that the press felt is disposedbetween the press roll and the web during passage of the press felt andthe web through the press nip. The transfer blanket extends through thepress nip such that the transfer blanket is disposed between the backingroll and the web during passage of the transfer blanket and the webthrough the press nip.

In another embodiment of the present invention, the dewatering sectionincludes an elongate press shoe for guiding the web. A backing rollco-operates with the press shoe for defining therebetween an extendednip for the passage therethrough of the web. A press felt extendsthrough the extended nip such that the press felt is disposed betweenthe press shoe and the web during passage of the press felt and the webthrough the extended nip. The transfer blanket extends through theextended nip such that the transfer blanket is disposed between thebacking roll and the web during passage of the transfer blanket and theweb through the extended nip. A roll is disposed downstream relative tothe extended nip for transferring the web from the transfer blanket andfor guiding the web towards the Yankee dryer.

In a more specific embodiment of the present invention, the loopedtransfer blanket is impervious to water. The arrangement is such thatduring transit of the web supported by the transfer blanket between theextended nip and the roll, rewetting of the web is inhibited.

Also, the roll is a transfer roll for transferring the web from thelooped transfer blanket.

Furthermore, the transfer apparatus includes a pressure roll which isdisposed downstream relative to the transfer roll.

Moreover, a pressure roll felt extends around the transfer roll and thepressure roll such that when the web is transferred by the transfer rollfrom the transfer blanket to the pressure roll felt, the web isthereafter guided and supported by the pressure roll felt to and aroundthe pressure roll. The arrangement is such that the web is transferredfrom the pressure roll felt to the Yankee dryer for drying of the web.

More specifically, the transfer roll is a suction transfer roll.

In another embodiment of the present invention, the roll is a suctionpressure roll for transferring the web from the looped transfer blanket.

Also, the transfer apparatus includes the pressure roll felt whichextends around the suction pressure roll such that when the web istransferred by the suction pressure roll from the transfer blanket tothe pressure roll felt, the web is thereafter guided and supported bythe pressure roll felt around the suction pressure roll so that the webis transferred from the pressure roll felt to the Yankee dryer fordrying of the web.

Additionally, a press section is disposed upstream relative to theextended nip. The press section includes a press roll.

A further backing roll co-operates with the press roll for definingtherebetween a press nip for the passage therethrough of the web.

Also, a pick up felt extends through the press nip such that the pick upfelt is disposed between the press roll and the web during passage ofthe pick up felt and the web through the press nip.

A further press felt extends through the press nip such that the furtherpress felt is disposed between the further backing roll and the webduring passage of the further press felt and the web through the pressnip.

Furthermore, a suction roll is disposed downstream relative to the pressnip and upstream relative to the extended nip. The suction rollco-operates with the further press felt for transferring the web fromthe further press felt to the press felt.

Additionally, the web is disposed between the further press felt and thepress felt.

Moreover, the pick up felt co-operates with a forming section fortransferring the web from the forming section to the pick up felt.

In a further embodiment of the present invention, a pressing rollco-operates with the backing roll for defining a pressing niptherebetween. The pressing nip is disposed upstream relative to theextended nip.

Furthermore, a pick up felt extends between the pressing roll and thebacking roll so that the web is disposed between the pick up felt andthe backing roll during passage of the web through the pressing nip. Thepick up felt picks up the web from an upstream forming section.

A first press roll co-operates with the pressing roll for defining afirst press nip therebetween. The first press nip is disposed upstreamrelative to the pressing nip.

Moreover, a pressing felt extends between the pressing roll and thefirst press roll so that the web is disposed between the pressing feltand the pick up felt during passage of the web through the first pressnip.

Many modifications and variations of the present invention will bereadily apparent to those skilled in the art by a consideration of thedetailed description contained hereinafter taken in conjunction with theannexed drawings which show a preferred embodiment of the presentinvention. However, such modifications and variations fall within thespirit and scope of the present invention as defined by the appendedclaims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a transfer apparatus according to afirst embodiment of the present invention;

FIG. 2 is a side elevational view of a second embodiment of the presentinvention;

FIG. 3 is a side elevational view of a third embodiment of the transferapparatus shown in FIGS. 1 and 2.

Similar reference characters with suffixes added thereto refer tosimilar parts throughout the various embodiments shown in the drawings.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a transfer apparatus generallydesignated 10 according to a first embodiment of the present invention.As shown in FIG. 1, the transfer apparatus 10 is for transferring alight weight web W from a dewatering section generally designated 12 toa Yankee dryer 14.

The transfer apparatus 10 includes a looped transfer blanket 16 which isdisposed between the dewatering section 12 and the Yankee dryer 14 forsupporting and transporting the web W from the dewatering section 12towards the Yankee dryer 14. The dewatering section 12 includes a pressgenerally designated 17. The press 17 defines a press nip 19 for thepassage therethrough of the web W. The press nip 19 assists indewatering the web W and guides the web W. A press felt 24 extendsthrough the press nip 19 and the transfer blanket 16 also extendsthrough the press nip 19. A roll 26 is disposed downstream relative tothe press nip 19 for transferring the web W from the transfer blanket 16and for guiding the web W towards the Yankee dryer 14.

In one embodiment of the present invention, as shown in FIG. 1, thepress 17 includes a press roll 21 for guiding the web W. A backing roll20 cooperates with the press roll 21 such that the press roll 21 and thebacking roll 20 define therebetween the press nip 19 for the passagetherethrough of the web W. The press felt 24 extends through the pressnip 19 such that the press felt 24 is disposed between the press roll 21and the web W during passage of the press felt 24 and the web W throughthe press nip 19. The transfer blanket 16 extends through the press nip19 such that the transfer blanket 16 is disposed between the backingroll 20 and the web W during passage of the transfer blanket 16 and theweb W through the press nip 19.

FIG. 2 is a side elevational view of a second embodiment of the presentinvention. As shown in FIG. 2, the dewatering section 12 a includes anelongate press shoe 18 for guiding the web Wa. A backing roll 20 aco-operates with the press shoe 18 for defining therebetween an extendednip 22 for the passage therethrough of the web Wa. A press felt 24 aextends through the extended nip 22 such that the press felt 24 a isdisposed between the press shoe 18 and the web Wa during passage of thepress felt 24 a and the web Wa through the extended nip 22. The transferblanket 16 a extends through the extended nip 22 such that the transferblanket 16 a is disposed between the backing roll 20 a and the web Waduring passage of the transfer blanket 16 a and the web Wa through theextended nip 22. A roll 28 a is disposed downstream relative to theextended nip 22 for transferring the web Wa from the transfer blanket 16a and for guiding the web Wa towards the Yankee dryer 14 a.

Those skilled in the art will appreciate that the location of the pressshoe 18 and the backing roll 20 a could be interchanged so that thetransfer blanket 16 a could serve the further function of a bearingblanket for supporting web Wa through the extended nip 22. In such anarrangement, the blanket 16 a would physically slide over the lubricatedsurface of the shoe 18 with the blanket 16 a disposed between the shoe18 and the web Wa.

In all of the embodiments of the present invention, the looped transferblanket 16, 16 a is impervious to water such that during transit of theweb W, Wa supported by the transfer blanket 16, 16 a between theextended nip 22 and the roll 28, 28 a, rewetting of the web W, Wa isinhibited.

As shown in FIG. 1, the roll 26 is a transfer roll for transferring theweb W from the looped transfer blanket 16.

Additionally, as shown in FIG. 1, the transfer apparatus 10 includes apressure roll 28 which is disposed downstream relative to the transferroll 26.

Moreover, a pressure roll felt 30 extends around the transfer roll 26and the pressure roll 28 such that when the web W is transferred by thetransfer roll 26 from the transfer blanket 16 to the pressure roll felt30, the web W is thereafter guided and supported by the pressure rollfelt 30 to and around the pressure roll 28. The arrangement is such thatthe web W is transferred from the pressure roll felt 30 to the Yankeedryer 14 for drying of the web W. Thus, the web is supported without anyopen draws between the extended nip 22 and the Yankee dryer 14.

More specifically, the transfer roll 26 is a suction transfer roll.

As shown in FIG. 2, the transfer apparatus 10 a includes a suctionpressure roll 28 a which transfers the web Wa from the looped transferblanket 16 a.

Also, the transfer apparatus 10 a includes a pressure roll felt 30 awhich extends around the suction pressure roll 28 a such that when theweb Wa is transferred by the suction pressure roll 28 a from thetransfer blanket 16 a to the pressure roll felt 30 a, the web Wa isthereafter guided and supported by the pressure roll felt 30 a aroundthe suction pressure roll 28 a so that the web Wa is transferred fromthe pressure roll felt 30 a to the Yankee dryer 14 a for drying of theweb Wa.

As shown in FIGS. 1 and 2, additionally, a press section generallydesignated 32 is disposed upstream relative to the press nip 19. Thepress section 32 includes a pressing roll 34.

A further backing roll 36 co-operates with the pressing roll 34 fordefining therebetween a pressing nip 38 for the passage therethrough ofthe web W, Wa.

Also, a pick up felt 40 extends through the pressing nip 38 such thatthe pick up felt 40 is disposed between the pressing roll 34 and the webW, Wa during passage of the pick up felt 40 and the web W, Wa throughthe pressing nip 38.

A further press felt 42 extends through the pressing nip 38 such thatthe further press felt 42 is disposed between the further backing roll36 and the web W, Wa during passage of the further press felt 42 and theweb W, Wa through the pressing nip 38.

Furthermore, a suction roll 44 is disposed downstream relative to thepressing nip 38 and upstream relative to the extended nip 22. Thesuction roll 44 co-operates with the further press felt 42 fortransferring the web W, Wa from the further press felt 42 to the pressfelt 24.

Additionally, the web W, Wa is disposed between the further press felt42 and the press felt 24, 24 a.

Moreover, the pick up felt 40 co-operates with a forming sectiongenerally designated 46 for transferring the web W, Wa from the formingsection 46 to the pick up felt 40.

FIG. 3 is a side elevational view of a further embodiment of thetransfer apparatus 10, 10 a shown in FIGS. 1 and 2. As shown in FIG. 3,a suction pressing roll 48 co-operates with the backing roll 20 b fordefining a nip 50 therebetween. The nip 50 is disposed upstream relativeto an extended nip 22 b.

Furthermore, a further pick up felt 58 extends between the suctionpressing roll 48 and the backing roll 20 b so that the web Wb isdisposed between the further pick up felt 58 and the backing roll 20 bduring passage of the web Wb through the nip 50. The further pick upfelt 58 picks up the web Wb from an upstream forming section 46 b.

An upstream backing roll 52 co-operates with the suction pressing roll48 for defining an upstream press nip 54 therebetween. The upstreampress nip 54 is disposed upstream relative to the nip 50.

Moreover, a pressing felt 56 extends between the suction pressing roll48 and the upstream backing roll 52 so that the web Wb is disposedbetween the pressing felt 56 and the suction pressing roll 48 duringpassage of the web Wb through the upstream press nip 54.

In operation of the transfer apparatus according to the presentinvention as shown in FIG. 1, the web W passes through a pressing nip 38and then passes through a press nip 19. The pressed web W is supportedby the transfer blanket 16 until the web is transferred from thetransfer blanket 16 to the pressure roll felt 30 by the transfer roll 26and then onto the Yankee dryer 14 all without any open draw of the webW.

In operation of the arrangement shown in FIG. 2, instead of a transferroll 26, the pressure roll 28 a which is a suction pressure rolltransfers the web Wa without any open draw thereof from the transferblanket 16 a to the Yankee dryer 14 a by means of a pressure roll felt30 a. Also, the press nip 19 is an extended nip 22.

In operation of the arrangement shown in FIG. 3, the extended nip 22 bis preceded by a nip 50 which utilises the backing roll 20 b of theextended nip 22 b.

Also, the nip 50 is preceded by an upstream press nip 54. Such upstreampress nip 54 may be optional.

The present invention provides a unique transfer apparatus fortransferring a light weight web such as tissue from a dewatering section12 to a Yankee dryer 14 without rewetting the web by a felt extendingthrough the dewatering section.

1. A transfer apparatus for transferring a light weight web from adewatering section to a Yankee dryer, said transfer apparatuscomprising: a looped transfer blanket disposed between the dewateringsection and the Yankee dryer for supporting and transporting the webfrom the dewatering section towards the Yankee dryer; the dewateringsection including: a press defining a press nip for the passagetherethrough of the web, said press nip assisting in dewatering the web,said press nip guiding the web; a press felt extending through saidpress nip; said transfer blanket extending through said press nip; and aroll disposed downstream relative to said press nip for transferring theweb from said transfer blanket and for guiding the web towards theYankee dryer.
 2. A transfer apparatus as set forth in claim 1 whereinsaid press includes: a press roll for guiding the web; a backing rollcooperating with said press roll such that said press roll and saidbacking roll define therebetween said press nip for the passagetherethrough of the web; said press felt extending through said pressnip such that said press felt is disposed between said press roll andthe web during passage of said press felt and the web through said pressnip; said transfer blanket extending through said press nip such thatsaid transfer blanket is disposed between said backing roll and the webduring passage of said transfer blanket and the web through said pressnip.
 3. A transfer apparatus as set forth in claim 1 wherein thedewatering section includes: an elongate press shoe for guiding the web;a backing roll co-operating with said press shoe for definingtherebetween an extended nip for the passage therethrough of the web; apress felt extending through said extended nip such that said press feltis disposed between said press shoe and the web during passage of saidpress felt and the web through said extended nip; said transfer blanketextending through said extended nip such that said transfer blanket isdisposed between said backing roll and the web during passage of saidtransfer blanket and the web through said extended nip; a roll disposeddownstream relative to said extended nip for transferring the web fromsaid transfer blanket and for guiding the web towards the Yankee dryer.4. A transfer apparatus as set forth in claim 3 wherein said loopedtransfer blanket is impervious to water such that, during transit of theweb supported by said transfer blanket between said extended nip andsaid roll, rewetting of the web is inhibited.
 5. A transfer apparatus asset forth in claim 3 wherein said roll is a transfer roll fortransferring the web from said looped transfer blanket; said transferapparatus further including: a pressure roll disposed downstreamrelative to said transfer roll; a pressure roll felt extending aroundsaid transfer roll and said pressure roll such that when the web istransferred by said transfer roll from said transfer blanket to saidpressure roll felt, the web is thereafter guided and supported by saidpressure roll felt to and around said pressure roll so that the web istransferred from said pressure roll felt to the Yankee dryer for dryingof the web.
 6. A transfer apparatus as set forth in claim 5 wherein saidtransfer roll is a suction transfer roll.
 7. A transfer apparatus as setforth in claim 3 wherein said roll is a suction pressure roll fortransferring the web from said looped transfer blanket; said transferapparatus further including: a pressure roll felt extending around saidsuction pressure roll such that when the web is transferred by saidsuction pressure roll from said transfer blanket to said pressure rollfelt, the web is thereafter guided and supported by said pressure rollfelt around said suction pressure roll so that the web is transferredfrom said pressure roll felt to the Yankee dryer for drying the web. 8.A transfer apparatus as set forth in claim 3 further including: a presssection disposed upstream relative to said extended nip.
 9. A transferapparatus as set forth in claim 8 wherein said press section includes: apressing roll; a further backing roll co-operating with said pressingroll for defining therebetween a pressing nip for the passagetherethrough of the web.
 10. A transfer apparatus as set forth in claim9 further including: a pick up felt extending through said pressing nipsuch that said pick up felt is disposed between said pressing roll andthe web during passage of said pick up felt and the web through saidpressing nip.
 11. A transfer apparatus as set forth in claim 9 furtherincluding: a further press felt extending through said pressing nip suchthat said further press felt is disposed between said further backingroll and the web during passage of said further press felt and the webthrough said pressing nip.
 12. A transfer apparatus as set forth inclaim 11 further including: a suction roll disposed downstream relativeto said pressing nip and upstream relative to said extended nip, saidsuction roll co-operating with said further press felt for transferringthe web from said further press felt to said press felt
 13. A transferapparatus as set forth in claim 12 wherein the web is disposed betweensaid further press felt and said press felt.
 14. A transfer apparatus asset forth in claim 10 wherein said pick up felt co-operates with aforming section for transferring the web from the forming section tosaid pick up felt.
 15. A transfer apparatus as set forth in claim 3further including: a suction press roll co-operating with said backingroll for defusing a nip therebetween, said nip being disposed upstreamrelative to said extended nip.
 16. A transfer apparatus as set forth inclaim 15 further including: a pick up felt extending between saidsuction pressing roll and said backing roll so that the web is disposedbetween said pick up felt and said backing roll during passage of theweb through said nip, said pick up felt picking up the web from anupstream forming section.
 17. A transfer apparatus as set forth in claim16 further including: an upstream backing roll co-operating with saidsuction pressing roll for defining an upstream press nip therebetween,said upstream press nip being disposed upstream relative to said nip.18. A transfer apparatus as set forth in claim 17 further including: apressing felt extending between said upstream backing roll and saidsuction pressing roll so that the web is disposed between said pressingfelt and said upstream backing roll during passage of the web throughsaid upstream press nip.
 19. A transfer apparatus for transferring alight weight web from a dewatering section to a Yankee dryer, saidtransfer apparatus comprising: a looped transfer blanket disposedbetween the dewatering section and the Yankee dryer for supporting andtransporting the web from the dewatering section towards the Yankeedryer; the dewatering section including: an elongate press shoe forguiding the web; a backing roll co-operating with said press shoe fordefining therebetween an extended nip for the passage therethrough ofthe web; a press felt extending through said extended nip such that saidpress felt is disposed between said press shoe and the web duringpassage of said press felt and the web through said extended nip; saidtransfer blanket extending through said extended nip such that saidtransfer blanket is disposed between said backing roll and the webduring passage of said transfer blanket and the web through saidextended nip; a roll disposed downstream relative to said extended nipfor transferring the web from said transfer blanket and for guiding theweb towards the Yankee dryer; and said looped transfer blanket beingimpervious to water such that during transit of the web supported bysaid transfer blanket between said extended nip and said roll, rewettingof the web is inhibited.
 20. A transfer apparatus for transferring alight weight web from a dewatering section to a Yankee dryer, saidtransfer apparatus comprising: a looped transfer blanket disposedbetween the dewatering section and the Yankee dryer for supporting andtransporting the web from the dewatering section towards the Yankeedryer; the dewatering section including: an elongate press shoe forguiding the web; a backing roll co-operating with said press shoe fordefining therebetween an extended nip for the passage therethrough ofthe web; a press felt extending through said extended nip such that saidpress felt is disposed between said press shoe and the web duringpassage of said press felt and the web through said extended nip; saidtransfer blanket extending through said extended nip such that saidtransfer blanket is disposed between said backing roll and the webduring passage of said transfer blanket and the web through saidextended nip; a roll disposed downstream relative to said extended nipfor transferring the web from said transfer blanket and for guiding theweb towards the Yankee dryer; said looped transfer blanket beingimpervious to water such that during transit of the web supported bysaid transfer blanket between said extended nip and said roll, rewettingof the web is inhibited; said roll being a transfer roll fortransferring the web from said looped transfer blanket; said transferapparatus further including: a pressure roll disposed downstreamrelative to said transfer roll; a pressure roll felt extending aroundsaid transfer roll and said pressure roll such that when the web istransferred by said transfer roll from said transfer blanket to saidpressure roll felt, the web is thereafter guided and supported by saidpressure roll felt to and around said pressure roll so that the web istransferred from said pressure roll felt to the Yankee dryer for dryingthe web; said transfer roll being a suction transfer roll; a presssection disposed upstream relative to said extended nip; said presssection including: a pressing roll; a further backing roll co-operatingwith said pressing roll for defining therebetween a pressing nip for thepassage therethrough of the web; a pick up felt extending through saidpressing nip such that said pick up felt is disposed between saidpressing roll and the web during passage of said pick up felt and theweb through said pressing nip; a further press felt extending throughsaid pressing nip such that said further press felt is disposed betweensaid further backing roll and the web during passage of said furtherpress felt and the web through said pressing nip; a suction rolldisposed downstream relative to said pressing nip and upstream relativeto said extended nip, said suction roll co-operating with said furtherpress felt for transferring the web from said further press felt to saidpress felt, the web being disposed between said further press felt andsaid press felt; and said pick up felt co-operates with a formingsection for transferring the web from the forming section to said pickup felt.